Trigeminal Nerve

Question 1

which CN emerges from the infratemporal fossa?

Answer 1

trigeminal nerve - mandibular portions (V3)

Question 2

______ fossa is superior to the zygomatic arch and communicates with the infratemporal fossa through a gap between the zygomatic arch and cranial bones

Answer 2

temporal fossa is superior to the zygomatic arch and communicates with the infratemporal fossa through a gap between the zygomatic arch and cranial bones

Question 3

_______ fossa communicates with the infratemporal fossa below through the foramen ovale and foramen spinosum. These foramina are openings in the intervening greater wing of sphenoid bone that transmit neurovascularature

Answer 3

middle cranial fossa communicates with the infratemporal fossa below through the foramen ovale and foramen spinosum. These foramina are openings in the intervening greater wing of sphenoid bone that transmit neurovascularature

Question 4

where is the parotid gland found?

Answer 4

par-otid = near the ear

largest of the salivary glands, located posterolateral part of the face

Question 5

mumps virus infection may result in ______ gland inflammation

Answer 5

parotid gland inflammation (parotiditis)

Question 6

which of the following is found deep and medial to the infratemporal fossa?
a. temporal fossa
b. middle cranial fossa
c. pterygopalatine fossa

Answer 6

c. pterygopalatine fossa

Question 7

what is contained in the infratemporal fossa? (4)

Answer 7

1. muscles of mastication
2. maxillary artery
3. pterygoid venous plexus
4. mandibular nerve (CN V3), otic ganglion, chorda tympani

Question 8

what are the muscles of mastication? (4)

Answer 8

1. temporalis: inserts on coronoid process of mandible to elevate mandible (closing the jaw)
2. masseter: inserts on ramus/angle (lateral) of mandible to elevate and protrude the mandible
3. lateral pterygoid: inserts on condylar neck of mandible to protrude/depress mandible and swing jaw to contralateral side (for grinding)
4. medial pteryoid: inserts on ramus (medial) of mandible to elevate mandible and assist with grinding

Question 9

Fracture of the mandibular condyle results in deviation of the jaw to affected side because…

Answer 9

… the lateral pterygoid muscle, which swings the jaw to the contralateral side, becomes injured, and the unopposed action of the muscle on the other side takes over

Question 10

what are the 3 parts of the maxillary artery?

Answer 10

1. mandibular: deep to the mandibular condyle, branches include middle meningeal artery and inferior alveolar artery (which becomes mental artery)
2. pterygoid: lateral to pterygoid muscle, branches to muscles of mastication
3. pterygopalatine: exits from infratemporal fossa and enters pterygopalatine fossa, branches include infraorbital artery (cheek), sphenopalatine artery (nasal cavity), posterior superior alveolar artery (teeth)

Question 11

_______ is the venous equivalent of the maxillary artery, as its tributaries correspond to the branches of the maxillary artery

Answer 11

pterygoid venous plexus is the venous equivalent of the maxillary artery, as its tributaries correspond to the branches of the maxillary artery

note: The numerous valveless (emissary) veins associated with the pterygoid venous plexus may spread of infection from the face to the cranial cavity.

Question 12

which division of CN V (trigeminal) is both sensory and motor? what are its branches? (4)

Answer 12

CN V3/ mandibular nerve —>
1. buccal branch (sensory)
2. auriculotemporal nerve (sensory) - carries PNS postganglionic fibers to parotid gland
3. lingual nerve (sensory) - carries taste fibers of chorda tympani (CN VII)
4. inferior alveolar nerve (mixed)

Question 13

what is the PNS innervation to each of the following?
a. parotid gland
b. submandibular gland
c. sublingual gland

Answer 13

a. parotid gland - CN IX
b. submandibular gland - CN VII
c. sublingual gland - CN VII

Question 14

Recall that parietal, frontal, greater wing of sphenoid, squamous part of temporal meet at a weak area of the skull, the _____.

Answer 14

Recall that parietal, frontal, greater wing of sphenoid, squamous part of temporal meet at a weak area of the skull, the pterion.

Fracture of the pterion may rupture the underlying frontal branch of the middle meningeal artery and result in a life-threatening hematoma that exerts pressure on the underlying cerebral cortex.

Question 15

what is the function/role of each of the trigeminal nerve sensory components?
a. spinal nucleus of V
b. main/principle nucleus
c. mesencephalic nucleus

Answer 15

a. spinal nucleus of V: pain/temp

b. main/principle nucleus: touch/pressure

c. mesencephalic nucleus: proprioception

Question 16

what is the role of the following nociceptive tracts?
a. spinothalamic
b. spinoreticular
c. spinomesencephalic

Answer 16

Spinothalamic Tract: discriminative aspects of pain and temperature
– to ventral posterior thalamus and then primary somatosensory cortex

•Spinoreticular Tract: emotional and arousal aspects of pain – to reticular formation as well as medial thalamus and then limbic centers

•Spinomesencephalic Tract: central modulation of pain
– to periaqueductal grey and then descending pathways

Question 17

Dejerine-Roussy Syndrome, aka Central Pain Syndrome

Answer 17

aka posterior thalamic pain syndrome: complication after stroke

—> neuropathic pain (location can vary), astereognosis, altered temperature perception